Today, before the House Committee on Veterans' Affairs, Peake said his department will now review all drugs prescribed by the VA to veterans with PTSD. Part of that review will be to examine the risks of medications on PTSD vets and to review proper notification procedures.

In one of the human experiments at the VA involving the anti-smoking drug Chantix, VA doctors waited more than three months after a statement was issued by the Food and Drug Administration before warning veterans about the possible serious side-effects, including suicide and neuropsychiatric behavior.

Peake said following the initial ABC News/ Washington Times report that letters would be sent to 32,000 veterans informing them that they are using a drug linked to suicide or violent behavior. Peake has said he "wished" the VA had not taken so long to warn veterans being used in the Chantix test. Today he reiterated his commitment to drug research using veterans.

"I commit to veterans, and to you, that I will be comprehensive and thorough in my investigations of how this study has been, and is being, conducted," Peake said in his statement to the committee. "I am determined that VA will remain a leader in the protection of human subjects and in veteran-centric research."

Lt. Col. Roger Charles (Ret.) who is now with the organization Soldiers for Truth said that giving Chantix to vets with PTSD is the equivalent of "mental health roulette".

Chantix has been linked to at least 40 suicides and 400 attempted suicides in the population at large, according to the FDA which published its first alert about the potential dangers of the drug on Nov. 20, 2007.

The FDA issued a second warning, and there was an alert from the drug's maker, Pfizer, before the VA finally began to warn veterans in the study on Feb. 29, 2008.

But even then, the VA omitted the word "suicide" from the cover letter sent to veterans.

Peake said the new VA warning letter he is sending will specify that suicide is one of the possible side-effects of Chantix.

Pfizer has maintained that the drug's benefits outweigh the risks and that it continues to do further studies on the drug.